1. Field of the Invention
The present invention is related to projectiles and, more particularly, is directed toward a technique and device which permits an explosive charge located in one portion of a projectile to be detonated in response to detonation of an explosive charge positioned in another portion of the projectile.
2. Description of the Prior Art
There exists in the family of military projectiles a cargo round which is designed to carry various payloads and eject them during flight. Such cargo may comprise, for example, radio jamming devices, and it is generally desired to eject such devices from the projectile at a predetermined point in time after the projectile has been launched. Cargo is normally ejected from the rear or base of the projectile by detonating an explosive charge which acts to remove a base plug from the projectile permitting the cargo to be ejected.
Detonation of the charge in the base of the projectile may be initiated by an electronic time fuze positioned at the forward portion of the projectile. Such a time fuze is preset to detonate its own explosive at a predetermined period of time after the projectile is launched. A problem exists in effectively translating the explosive charge of the time fuze into an electrical signal which may be utilized to detonate the explosive at the rear of the projectile.
A high explosive detonating cord known as Primacord has been used in the past to transmit a detonation from one point to another at the other end of the cord. Such a device, however, is unsuitable for the application discussed above, since the cord itself is detonated and anything along the path of the cord stands to be damaged or destroyed. Thus, the payload in the cargo projectile between the fuze and the rear base plug would be subjected to damage or destruction.
A need, therefore, arose to provide such a cargo-carrying projectile with a means for utilizing the explosive charge at the front end of the projectile to detonate the charge at the rear of the projectile, without destroying the payload positioned between the charges.
An early solution to this problem is taught in U.S. Pat. No. 4,335,655 which discloses a device for detonating an explosive in response to the detonation of a remote explosive without damaging any components positioned intermediate the two explosives. In this patent a permanent magnet having a coil of wire positioned about it is placed adjacent to one of the explosives, ad the output from the coil is connected to the detonator for the second explosive. When the first explosive is detonated, the permanent magnet is destroyed to thereby collapse the magnetic field traversing the coil. The collapse of the magnetic field generates a voltage which is transmitted to the detonator for the second explosive for initiating detonations of that second explosive. There however are some shortcomings with the device disclosed in U.S. Pat. No. 4,335,655 in that the voltage pulse generated by this switch lasts for only a few microseconds. It is, therefore, not adequate in situations where a continuous voltage is required to detonate a series of explosive charges or to sequentially send an electrical signal to other electrical or electronic components.
In addition there was also a critical need to develop a switch mechanism in which, upon activation of the switch, the contact elements would remain fully closed to provide a continuous voltage pulse that lasts for several seconds; i.e, the switch elements must be prevented from bouncing apart and accidentally reopening the electrical circuit.